Tire Inner Liner Adhesion Using Aromatic Carboxylic Acid
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Solution Overview
Problem
Compounding a large amount of epoxidized natural rubber into a rubber composition to improve adhesion between a film and a rubber layer in pneumatic tires increases production costs due to the expense of epoxidized natural rubber.
Innovation Solution
Incorporating an aromatic carboxylic acid, such as salicylic acid, into the rubber composition with epoxidized natural rubber and butadiene rubber to enhance adhesion without requiring a large amount of epoxidized natural rubber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large amount of epoxidized natural rubber is compounded into the rubber composition to improve adhesion between the film and rubber layer, then adhesion is improved, but production cost increases due to the expense of epoxidized natural rubber
Solution Approach 1:
An aromatic carboxylic acid with pKa of 1.5 to 4.0 is introduced as a mediator substance in the rubber composition. This intermediary compound facilitates adhesion between the thermoplastic resin film and rubber layer, allowing reduced use of expensive epoxidized natural rubber while maintaining bonding strength through the acid's interaction with both polymer surfaces
Solution Approach 2:
The invention changes the chemical parameter of the rubber composition by incorporating aromatic carboxylic acid compounds with specific pKa values (1.5 to 4.0). This parameter change enables the system to achieve adequate adhesion with lower amounts of epoxidized natural rubber, thereby reducing material cost while maintaining bonding performance
2Strength
If a large amount of epoxidized natural rubber is used to improve adhesion, then adhesion is improved, but low-temperature durability deteriorates due to increased cracking
Solution Approach 1:
The aromatic carboxylic acid acts as a mediator that provides adhesion promotion without the negative low-temperature effects of high epoxidized natural rubber content. The acid compound enables bonding while the rubber composition maintains its elastomeric flexibility at low temperatures, preventing cracking
Solution Approach 2:
By changing the chemical composition parameters to include aromatic carboxylic acid with specific pKa ranges, the invention achieves adhesion promotion while maintaining the rubber's low-temperature flexibility. This parameter adjustment prevents the embrittlement and cracking associated with high epoxidized natural rubber content
Data Source
AI summary
With respect to a laminate of a film formed of a thermoplastic resin or thermoplastic elastomer composition and a layer formed of a rubber composition in which an epoxidized natural rubber is blended, the adhesion between the film and the layer of the rubber composition is improved without using a large amount of the epoxidized natural rubber. A laminate of a film formed of a thermoplastic resin or thermoplastic elastomer composition and a layer formed of a rubber composition, said laminate being characterized in that: 5-60% by mass of a rubber component contained in the rubber composition is composed of an epoxidized natural rubber and 20-50% by mass of the rubber component is composed of a butadiene rubber; and the rubber composition contains an unsubstituted or substituted aromatic carboxylic acid having a pKa of 1.5-4.0 in an amount of 0.5-5 parts by mass per 100 parts by mass of the rubber component.